A new mandarin mandarin cultivar Citrus reticulata is described. The new variety, designated xe2x80x98Dityxe2x80x99 is desirable to the consumer because of the orange-red color of its fruit and to the commercial grower because of its appearance and mid-late fruit ripening.
The present invention relates to a new and distinct variety of mandarin cultivar Citrus reticulata developed by inventors Aliza Vardi, Pinchas Spiegel-Roy, Ahuva Frydman-Shani, Avraham Elchanati and Hana Neumann in Bet Dagan, Israel from a selection of plants grown from irradiated bud wood of the cultivar xe2x80x98Editxe2x80x99 (not patented).
Asexual reproduction by conventional bud grafting of the new variety at the Agriculture Research Organization Volcani Center in Bet Dagan, Israel, has shown that the new characteristics are stabilized and permanently fixed through successive propagation.
The objective in breeding the present new tree variety, assigned the denomination xe2x80x98Dityxe2x80x99, was to obtain a mid-late season ripening mandarin citrus with few of no seeds (0-3) per fruit. In the spring of 1989, about 300 buds of the mandarin cultivar, xe2x80x98Editxe2x80x99, were irradiated at the Nahal Soreq Nuclear Center, Yavne, Israel, by exposure to 3.5 kh of gamma radiation from a Co60 source. Troyer and sour orange nucellar rootstocks were bud grafted with the individual buds of irradiated xe2x80x98Editxe2x80x99 bud wood and labeled mV1. Six to nine months after grafting the irradiated budwood, individual buds from the mV1 plants were re-grafted on Troyer and Sour orange nucellar rootstocks to establish about 500 mV2 plants.
Field planting was established from container grown mV2 plants in the spring of 1992 and 1993. The first fruits were observed in December-January 1995-1996 and a second observation made during December-January of 1996-1997.
The selection xe2x80x9813/2/94xe2x80x99, was distinguished from xe2x80x98Editxe2x80x99 in having fruit with 0-3 seeds per fruit compared with 3-11 seeds for xe2x80x98Editxe2x80x99 and in having low pollen fertility compared with xe2x80x98Editxe2x80x99. Typically, 3% of the pollen grains of 13/2/94 were stained by acetocarmine compared with 80% staining for xe2x80x98Editxe2x80x99.
Some characteristics of selection 13/2/94, designated xe2x80x98Dityxe2x80x99, compared with xe2x80x98Editxe2x80x99 are shown in Table 1.
The following is a detailed description of the new mandarin citrus variety based on observations made under typical Israeli grove conditions. Descriptions are based on observations of 3-4 year old plants grown in Bet Dagan, Israel. Color designations are based on comparisons determined from the R.H.S Colour Chart published by The Royal Horticultural Society.
The tree shape and fruit appearance are similar to that of xe2x80x98Editxe2x80x99. The tree is vigorous. Small thorns are usually present in the leafy part of branches. Main branches have an upright attitude and young shoots have no anthocyanin coloration at the tip. The bearing of the tree is regular and the productivity is relatively high, about the same as for xe2x80x98Editxe2x80x99. The canopy is moderately dense.
The bark of the young shoots is initially smooth and green gradually turning into a smooth brown-gray.
The leaf blades are firm, without undulation and concave in cross section. The leaves are similar to those of xe2x80x98Editxe2x80x99 and are lancelolate, small to medium in size and without wings.
Th characteristics of the flowering and the flower parts are similar to those of xe2x80x98Editxe2x80x99. Flowering for both occurs at the end of March and beginning of April in Bet Dagan, Israel. Both xe2x80x98Dityxe2x80x99 and xe2x80x98Editxe2x80x99 produce about the same number of flowers and flower drop for both occurs in June. Terminal flower buds have no anthocyanin coloration. Flowers are borne singly and have an average number of stamens (about 20) with complete style development. Anther color is pale yellow to white. Pollen fertility is low as indicated by the observation that only 2% of the pollen grains were stained with acetocarmine in a test conducted at the Agricultural Research Organization, the Volcani Center, Israel, as compared with about 80% for xe2x80x98Editxe2x80x99 pollen grain.
The fruit is seedless or has few seeds, 0-3 seeds, even when optimal pollination conditions are employed. This compares with about 0-11 seeds per fruit in xe2x80x98Editxe2x80x99. In other respects the fruit characteristics of xe2x80x98Dityxe2x80x99 are in the range of the parent cv. xe2x80x98Editxe2x80x99. The fruit shape is oblate and medium-sized. When 50 fruits were measured, the fruit had an average weight 94.6 grams, an average height 44.7 mm, and an average diameter of 65 mm. The fruit has a moderately depressed stalk end. The fruit surface is usually smooth with an orange color, RHS 30B, on The Royal Horticultural Society of London Colour Chart, and bears an average number of conspicuous rind oil glands (30 per cm2). Fruit ripening does not differ from outside of the canopy to the inside, but the fruit color of the outside canopy is a little brighter compared to the fruit color of the inside canopy. There is no persistence of the style and the areola is not completely developed. A navel is absent or rare. The rind is thin and easy to peel.
The color of the albedo is white and the flesh is orange in color. The fruit contains 9-11 segments and is very juicy. The external color of the seeds (when fresh) and dry is ivory. The internal seed coat is white and the cotyledons are white. Monoembryonic seeds are present. The seed sizes, shape and texture are similar to that of the parent xe2x80x98Editxe2x80x99. The fruit reaches maturity at the beginning of December to the end of January. The ripening of the fruit on the tree and within the fruit is uniform. Fruit remaining on the tree does not regreen and begins to lose quality at the beginning of February. If there is a heavy crop and the fruits are not picked during the ripening season, the tree may become alternate bearing (produces less fruit the following season). Pre-harvest drop of both developed and undeveloped fruit is similar to that of the parent cv. xe2x80x98Editxe2x80x99.